BF998/BF998R/BF998RW
Vishay Semiconductors
N–Channel Dual Gate MOS-Fieldeffect Tetrode,
Depletion Mode
Electrostatic sensitive device.
Observe precautions for handling.
Applications
Input and mixer stages in UHF tuners.
Features
D
D
D
D
D Low input capacitance
D High AGC-range
D High gain
Integrated gate protection diodes
Low noise figure
Low feedback capacitance
High cross modulation performance
2
1
1
13 579
94 9279
3
3
BF998R Marking: MOR
Plastic case (SOT 143R)
1 = Source, 2 = Drain, 3 = Gate 2, 4 = Gate 1
2
13 654
4
95 10831
94 9278
4
4
BF998 Marking: MO
Plastic case (SOT 143)
1 = Source, 2 = Drain, 3 = Gate 2, 4 = Gate 1
1
2
13 566
3
BF998RW Marking: WMO
Plastic case (SOT 343R)
1 = Source, 2 = Drain, 3 = Gate 2, 4 = Gate 1
Absolute Maximum Ratings
Tamb = 25_C, unless otherwise specified
Parameter
Drain - source voltage
Drain current
Gate 1/Gate 2 - source peak current
Gate 1/Gate 2 - source voltage
Total power dissipation
Channel temperature
Storage temperature range
Document Number 85011
Rev. 4, 23-Jun-99
Test Conditions
Tamb ≤ 60 °C
Symbol
Value
VDS
12
ID
30
±IG1/G2SM
10
±VG1S/G2S
7
Ptot
200
TCh
150
Tstg
–65 to +150
Unit
V
mA
mA
V
mW
°C
°C
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BF998/BF998R/BF998RW
Vishay Semiconductors
Maximum Thermal Resistance
Tamb = 25_C, unless otherwise specified
Parameter
Test Conditions
Channel ambient on glass fibre printed board (25 x 20 x 1.5) mm3
plated with 35mm Cu
Symbol
RthChA
Value
450
Unit
K/W
Electrical DC Characteristics
Tamb = 25_C, unless otherwise specified
Parameter
Drain - source
breakdown voltage
Gate 1 - source
breakdown voltage
Gate 2 - source
breakdown voltage
Gate 1 - source
leakage current
Gate 2 - source
leakage current
Drain current
Gate 1 - source
cut-off voltage
Gate 2 - source
cut-off voltage
Test Conditions
ID = 10 mA,
–VG1S = –VG2S = 4 V
±IG1S = 10 mA,
VG2S = VDS = 0
±IG2S = 10 mA,
VG1S = VDS = 0
±VG1S = 5 V,
VG2S = VDS = 0
±VG2S = 5 V,
VG1S = VDS = 0
VDS = 8 V, VG1S = 0,
VG2S = 4 V
Type
BF998/BF998R/
BF998RW
BF998A/BF998RA/
BF998RAW
BF998B/BF998RB/
BF998RBW
VDS = 8 V, VG2S = 4 V,
ID = 20 mA
VDS = 8 V, VG1S = 0,
ID = 20 mA
Symbol
V(BR)DS
Min
12
±V(BR)G1SS
7
14
V
±V(BR)G2SS
7
14
V
±IG1SS
50
nA
±IG2SS
50
nA
18
mA
IDSS
4
IDSS
4
IDSS
9.5
Typ
Max Unit
V
10.5 mA
18
mA
–VG1S(OFF)
1.0
2.0
V
–VG2S(OFF)
0.6
1.0
V
Typ
24
2.1
1.1
25
1.05
28
20
Max
Unit
mS
pF
pF
fF
pF
dB
dB
dB
dB
dB
Electrical AC Characteristics
VDS = 8 V, ID = 10 mA, VG2S = 4 V, f = 1 MHz , Tamb = 25_C, unless otherwise specified
Parameter
Forward transadmittance
Gate 1 input capacitance
Gate 2 input capacitance
Feedback capacitance
Output capacitance
Power g
gain
AGC range
Noise figure
g
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Test Conditions
VG1S = 0, VG2S = 4 V
GS = 2 mS, GL = 0.5 mS, f = 200 MHz
GS = 3,3 mS, GL = 1 mS, f = 800 MHz
VG2S = 4 to –2 V, f = 800 MHz
GS = 2 mS, GL = 0.5 mS, f = 200 MHz
GS = 3,3 mS, GL = 1 mS, f = 800 MHz
Symbol
y21s
Cissg1
Cissg2
Crss
Coss
Gps
Gps
DGps
F
F
Min
21
16.5
40
1.0
1.5
2.5
Document Number 85011
Rev. 4, 23-Jun-99
BF998/BF998R/BF998RW
Vishay Semiconductors
Typical Characteristics (Tamb = 25_C unless otherwise specified)
250
200
150
100
50
0
20
40
60
80
1V
12
8
0
4
0
–0.6
100 120 140 160
Tamb – Ambient Temperature ( °C )
–0.2
0.2
0.6
1.0
1.4
VG2S – Gate 2 Source Voltage ( V )
12817
Figure 1. Total Power Dissipation vs.
Ambient Temperature
Figure 4. Drain Current vs. Gate 2 Source Voltage
3.0
VG1S= 0.6V
VG2S= 4V
25
C issg1 – Gate 1 Input Capacitance ( pF )
30
ID – Drain Current ( mA )
16
VG1S= –1V
96 12159
20
0.4V
15
0.2V
10
0
–0.2V
5
–0.4V
0
0
2
4
6
8
10
VDS – Drain Source Voltage ( V )
12812
VDS=8V
VG2S=4V
f=1MHz
2.0
1.5
1.0
0.5
0
–2
–1.5 –1.0 –0.5
0.0
0.5
1.0
1.5
VG1S – Gate 1 Source Voltage ( V )
Figure 5. Gate 1 Input Capacitance vs.
Gate 1 Source Voltage
3.0
20
16
3V
2V
6V
C oss – Output Capacitance ( pF )
VDS= 8V
5V
1V
4V
12
8
0
4
0
–0.8
2.5
12863
Figure 2. Drain Current vs. Drain Source Voltage
ID – Drain Current ( mA )
3V
2V
5V
VDS= 8V
0
12816
4V
20
ID – Drain Current ( mA )
P tot – Total Power Dissipation ( mW )
300
VG2S=–1V
–0.4
0.0
0.4
0.8
2.0
1.5
1.0
0.5
0
2
1.2
VG1S – Gate 1 Source Voltage ( V )
Figure 3. Drain Current vs. Gate 1 Source Voltage
Document Number 85011
Rev. 4, 23-Jun-99
VG2S=4V
f=1MHz
2.5
12864
4
6
8
10
12
VDS – Drain Source Voltage ( V )
Figure 6. Output Capacitance vs. Drain Source Voltage
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BF998/BF998R/BF998RW
Vishay Semiconductors
10
1V
–10
0
–20
–0.2V
–30
–0.4V
–40
10mA
–20
–0.5
0.0
0.5
1.0
400MHz
20mA
700MHz
–25
1000MHz
–35
1.5
VG1S – Gate 1 Source Voltage ( V )
1300MHz
0
4
8
12
16
20
24
28
32
Re (y21) ( mS )
12821
Figure 7. Transducer Gain vs. Gate 1 Source Voltage
Figure 10. Short Circuit Forward Transfer Admittance
9
32
VG2S=4V
VDS=8V
f=1MHz
24
7
3V
20
16
2V
12
f=1300MHz
8
Im ( y22) ( mS )
y21s – Forward Transadmittance ( mS )
ID=5mA
–15
–40
12818
28
–10
f=100MHz
–30
VG2S=–0.8V
–50
–1
–5
VDS=8V
VG2S=4V
f=100...1300MHz
0
Im ( y21) ( mS )
– Transducer Gain ( dB )
0
2
S 21
5
4V
3V
2V
f= 800MHz
8
6
1000MHz
5
700MHz
4
3
1V
4
1
0
0
0
4
100MHz
0
8
12
16
20
24
0
28
ID – Drain Current ( mA )
12819
VDS=15V
VG2S=4V
ID=10mA
f=100...1300MHz
400MHz
2
12822
Figure 8. Forward Transadmittance vs. Drain Current
0.25
0.50
0.75
1.00
1.25
1.50
Re (y22) ( mS )
Figure 11. Short Circuit Output Admittance
20
f=1300MHz
18
16
Im ( y11 ) ( mS )
14
1000MHz
12
10
700MHz
8
6
VDS=8V
VG2S=4V
ID=10mA
f=100...1300MHz
400MHz
4
2
100MHz
0
0
2
4
6
8
10
12
14
Re (y11) ( mS )
12820
Figure 9. Short Circuit Input Admittance
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Document Number 85011
Rev. 4, 23-Jun-99
BF998/BF998R/BF998RW
Vishay Semiconductors
VDS = 8 V, ID = 10 mA, VG2S = 4 V , Z0 = 50
W
S12
S11
j
90°
120°
j0.5
60°
j2
150°
j0.2
ÁÁÁ
ÁÁÁ
ÁÁÁÁÁÁ
ÁÁÁ
ÁÁÁ
ÁÁÁÁÁÁ
0
30°
j5
0.2
0.5
1
2
1200
1300MHz
1
5
200
100
180°
0.08
0.16
0°
100
–j0.2
–j5
1300MHz
–150°
1000
–j0.5
–30°
–j2
–120°
–j
12 960
–60°
–90°
12 973
Figure 12. Input reflection coefficient
Figure 14. Reverse transmission coefficient
S21
S22
j
90°
120°
60°
700
j0.5
1000
400
150°
j2
30°
j0.2
1300MHz
100
180°
1
2
0°
0
j5
ÁÁÁ
ÁÁÁ
ÁÁ
ÁÁ
ÁÁ
ÁÁÁ
ÁÁÁ
ÁÁÁÁÁÁ
0.2
0.5
1
2
5
100
–j0.2
–150°
1
–j5
–30°
1300MHz
–j0.5
–120°
12 962
–90°
Figure 13. Forward transmission coefficient
Document Number 85011
Rev. 4, 23-Jun-99
–j2
–60°
12 963
–j
Figure 15. Output reflection coefficient
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5 (8)
BF998/BF998R/BF998RW
Vishay Semiconductors
Dimensions of BF998 in mm
96 12240
Dimensions of BF998R in mm
96 12239
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6 (8)
Document Number 85011
Rev. 4, 23-Jun-99
BF998/BF998R/BF998RW
Vishay Semiconductors
Dimensions of BF998RW in mm
96 12238
Document Number 85011
Rev. 4, 23-Jun-99
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7 (8)
BF998/BF998R/BF998RW
Vishay Semiconductors
Ozone Depleting Substances Policy Statement
It is the policy of Vishay Semiconductor GmbH to
1. Meet all present and future national and international statutory requirements.
2. Regularly and continuously improve the performance of our products, processes, distribution and operating
systems with respect to their impact on the health and safety of our employees and the public, as well as their
impact on the environment.
It is particular concern to control or eliminate releases of those substances into the atmosphere which are known as
ozone depleting substances ( ODSs ).
The Montreal Protocol ( 1987 ) and its London Amendments ( 1990 ) intend to severely restrict the use of ODSs and
forbid their use within the next ten years. Various national and international initiatives are pressing for an earlier ban
on these substances.
Vishay Semiconductor GmbH has been able to use its policy of continuous improvements to eliminate the use of
ODSs listed in the following documents.
1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments respectively
2 . Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental
Protection Agency ( EPA ) in the USA
3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C ( transitional substances ) respectively.
Vishay Semiconductor GmbH can certify that our semiconductors are not manufactured with ozone depleting
substances and do not contain such substances.
We reserve the right to make changes to improve technical design and may do so without further notice.
Parameters can vary in different applications. All operating parameters must be validated for each customer application
by the customer. Should the buyer use Vishay-Semiconductors products for any unintended or unauthorized application, the
buyer shall indemnify Vishay-Semiconductors against all claims, costs, damages, and expenses, arising out of, directly or
indirectly, any claim of personal damage, injury or death associated with such unintended or unauthorized use.
Vishay Semiconductor GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany
Telephone: 49 ( 0 ) 7131 67 2831, Fax number: 49 ( 0 ) 7131 67 2423
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Document Number 85011
Rev. 4, 23-Jun-99